In Escherichia coli B/r, the segregation of the DNA strands into progeny cells is an oriented process, suggesting that the bacterial genome is permanently associated with the cell envelope. The objective of the proposed research is to determine if this association reflects a causal coordination between the synthesis of the envelope and DNA replication. The study will include the analysis of 1) the pattern of envelope synthesis during the cell division cycle, 2) the effect of limitation of membrane and wall precursors on the pattern of DNA replication and envelop composition, 3) the coordination between segregation of the envelope and the DNA strands into progeny cells, and 4) the influence of the attachment of DNA to the cell membrane on the symmetry of initiation of rounds of DNA replication on the bacterial chromosome. The study will be performed on the gram-negative bacterium Escherichia coli B/r because or the extensive information available on the physiology of this cell at several growth rates and the possibility of obtaining synchronous populations with minimal perturbation of balanced growth conditions.